Forget the 'simulated universe', say boffins, no simulator could hit the required scale

That “we live in a simulation" trope being advanced by Elon Musk and some folk on the fringes of science? Fuggeddaboutit, because it's impossible to build a simulator that would reproduce what humans already know about quantum systems. That's the confident conclusion drawn from a paper that revels in the title “Quantized …

[Pascal Monett]

"To model just a few hundred electrons needs a computer bigger than the universe"

Okay, I know I'm the village idiot next to these guys and I'm sure they know what they're talking about, but that sentence really bugs me. It is probably due to the sentence further down that says that adding another particle doubles the size of the model, so they just did an exponential of 2 to the 100th power and yeah, for sure that's big, but is that really how the simulator would work ?

What if it was a quantum simulator and each particle was thus analyzed by a quantum dot that considered all of its possible positions simultaneously ? Isn't that how it should work ?

I don't know. It's way too early for this anyway. I'm quitting this before the headaches start.

[DropBear]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

I'm finding it remarkably bold to attempt to infer any conclusions about our universe's simulated nature from any findings regarding complexity considering that IF we are indeed in a simulation we have not the faintest idea about a) what kind of hardware does the simulation / what exactly a unit of it can simulate (one would expect a very different performance from an ALU and an FPGA implementing the same complex logic after all), b) how mind-bogglingly large it might be compared even to the vastness of our own universe and c) how much of unobserved complexity it does simulate down to its most accurate level and how much of it gets fudged by ingenious shortcuts and workarounds when we're not looking at it and finally d) how much it redirects intractable complexity from the space into the time domain - ie. how much it slows down (not something that we would be able to detect as long as the rest of the simulation is kept in sync with the slow bits) whenever it needs to recurse deep into some detail (nobody said we're running at a stable 100FPS in "outside world" terms - we might be a slow and unsteady as fuck scientific simulation...)

Let us not forget for instance that any detail of interest of a fractal image down to arbitrary resolution CAN be calculated on-demand never bothering with calculating "all" (for whatever arbitrary limits we care about) the image at the same resolution, working from a very much uncomplicated formula. FFS, we don't even have any idea how many dimensions the outsiders might have at their disposal to expand their mainframe into - it's not like all simulations we run are in full 3D!

So yeah, I'm fully prepared to believe those guys that were we trying to simulate ourselves, especially in a naive brute-force fashion, the ramping complexity would prevent it really quickish-like; what I'm much less prepared to believe is that they know what they talk about when they say "impossible" (or more specifically, that they don't need to rely on a massive heap of embarrassingly arbitrary assumptions to say that).

[Doctor Syntax]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

e) If I (and this has to be expressed in 1st person terms) exist in a simulation then none of you, el Reg or anyone else exist except as inputs presented to me. That includes the papers you write which I'd have no way of verifying as I have no access to the observatories that don't exist. So if one were to consider oneself as living in a simulation one doesn't have to believe that everything an entire universe is being simulated all the time because nothing outside one's immediate experience needs to be simulated all the time; it can just be instantiated as needed.

[Yes Me]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

Actually it needs a computer which is exactly the same size as the universe. The universe is, existentially, an exact simulation of itself. That doesn't mean the paper is wrong. Those electrons don't exist in isolation; because of entanglement, it's quite artificial to separate them from the rest of the Universe, and if you do so, you're going to have simulate the effect of the rest of the Universe on them... so you're going to have to simulate the whole Universe anyway, which of course needs a simulator that contains more bits than the whole Universe, even if it's a quantum computer, and even if quantum theory is the true theory.

All we can ever simulate, even in principle, is an approximation.

[fishdog]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

"If I (and this has to be expressed in 1st person terms) exist in a simulation then none of you, el Reg or anyone else exist except as inputs presented to me."

This is a possible consequence, not a necessary consequence.

Don't get me wrong, I agree with you, such a solution would be n to the nnnth power easier to simulate, but if you're going to critique others logic you have to accept criticism of your own, as well.

My programming told me to say that.

[Muscleguy]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

Musk's original claim was that we can simulate reality to details that look photorealistic so therefore simulation is possible ignores the fact that simulation games use things like ray tracing and are built from triangles etc which mean the Planck length in the 'photorealistic' simulations is HUGE compares with the Planck length we have measured in this universe.

It would seem to me that the Planck length would ineluctably have to increase for each level of simulation compared to the previous one to avoid the problems this paper details. The shortcuts you describe in effect very greatly, orders of magnitude increase the Planck length. There is no getting away from that.

BTW my wife was finishing up her CompSci degree in the department of the University of Otago which did the Americas Cup simulations and graphics in the early '80s which broke the ground of what had been possible so despite being a mere biologist I have an inkling of the technologies, methods and issues involved. The effective Planck length of those simulations would have been of the order of whole centimetres.

[tekHedd]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

"any detail of interest of a fractal image down to arbitrary resolution CAN be calculated on-demand"

It seems to me that the very nature of quantum physics suggests that perhaps the system is designed intentionally such that nothing needs to be known until it is observed/needed. But what do I know? Nothing until I observe it, apparently. :)

[Aitor 1]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

It is bullocks, it can be demonstrated that of course you cannot model the universe, but you can model a relatively small part of the universe.. that we do not know HOW to do it does not mean that it CANNOT be done..

Anyway, it matters not if it is simulated or not, it makes 0 difference. I vote for non simulated, but who cares?

[Alex Read]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

That, and the title bug me... there's no need for the comma before the AND

[Sam Therapy]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

Yep, there is. Read up on the Oxford comma:

https://en.wikipedia.org/wiki/Serial_comma

[John Smith 19]

" for sure that's big, but is that really how the simulator would work ?"

IIRC the point about a quantum computer is that it computes all answers to a problem EG simulating a universe at the same time.

IOW it's not just the best computer available, it would be the best computer that could ever be available. *

And it's still not powerful enough to handle this problem. :-(

*Keep in mind that what physicists call a computer can just as easily be an analog computer for a specific task, which is how I'd describe a lot of the reports of "quantum computers" I've seen over the years. Great for the class of problems it's built for, but not programmable in the sense of actually writing a program, loading it and running it.

[Just Enough]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

The correct answer to this statement should be; "So?" If we are in a simulation, we have absolutely no concept how much bigger the environment is outside of the simulation.

Plus the whole point of models is to simplify things. Electrons are models. Effective models, because the mostly explain the behaviour of what we know of electrons in terms that we understand. But you don't complicate a model with information that you don't need for the immediate task at hand. Simulations are no different.

[nijam]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

> If we are in a simulation, we have absolutely no concept how much bigger the environment is outside of the simulation.

And perhaps more relevant, what the laws of physics are in that environment. There's certainly no requirement for them to be the same as those we (or our experiments) experience.

But as has already been mentioned, it really doesn't matter.

[scrubber]

Re: "To model just a few hundred electrons needs a computer bigger than the universe"

By definition a computer EXACTLY the size of the universe IS able to model somewhat larger than just a few hundred electrons.

Strikes me that they may be good at maths, but they're pretty poor at logic. Might be all the quantum in their heads.

[Michael H.F. Wilkinson]

Doesn't really surprise me

I once heard an astronomer explain that it is already impossible to compute all possible binary images of 2048x2048 pixels, not because the code is hard to write, but because the 2^2048x2048 bit flips needed cannot be computed if the energy budget for computation is the rest energy of the visible universe, and the time available is the Hubble time (13.8 billion years or so). This was true even if you brought the cost of a bit flip down to the quantum limits posed by the quantum uncertainty. I would expect simulating the entire universe down to quantum scales requires a tad more that 2^2048x2048 bit flips.

[DainB]

Re: Doesn't really surprise me

Why do you need simulate all atoms in a star few hundred LY away if all observer will be able to see is just one pixel ?

[Yes Me]

Re: Doesn't really surprise me

"Why do you need simulate all atoms in a star..."

You don't, if all you care about is one pixel down here. But you do, if you care about how the star works internally in detail. However, it's a pretty uninteresting question in terms of what is actually possible.

[Aitor 1]

Re: Doesn't really surprise me

Of course, but there is no need to do that in order to simulate the universe.

It is also impossible to render all the possible images out of a 3D MMO game using all the energy of the universe, yet people play quite ok.

So this is just bullshit, and the ppl producing it are mathematicians at heart, so they know it.

[Anonymous Coward]

Re: Don't need to simulate that star a few billion light years away...

But you do... as in, currently we can test to see if it matches the laws of physics. We have eyes/telescopes and other things effected on the macro scale (gravity) and quantum scale (QM effects).

If it is not mathematically simulated, then we would get contradicting results on multiple tests/observations/detectors.

It COULD be procedural simulation, using an algorithm to pick out the number of photons from a stars light. In the same way the original Elite did on just a few K of data and computation... except one big problem.

Quantum Mechanics and the Bell's inequality prove that this cannot be the case for our universe (but could for others, for example those in the computer game Elite ;) ). The actual results are given at that time, and cannot be pre-calculated.

[defiler]

Re: Don't need to simulate that star a few billion light years away...

Is this the bit where I say "Right on, Commander"?

[CrazyOldCatMan]

Re: Don't need to simulate that star a few billion light years away...

Is this the bit where I say "Right on, Commander"?

I prefer "smoke me a kipper, I'll be back for breakfast"..

[John Smith 19]

"already impossible to compute all possible binary images of 2048x2048 pixels,"

Which is really not very big at all, especially if they meant a pure 1 bit per pixel image. That would be 1/2 MB.

Which is sort of depressing

[Anonymous Coward]

Really ?

If this universe is a simulation, who's to say that the physics in this simulated universe is the same as in the world our simulation is running in ?

[Christian Berger]

As well as...

our universe being in the same order of magnitude of space than the universe the computer is in.

This is simply an undecidable problem.

[Anonymous Coward]

Re: As well as...

The usual computational questions might give some answer. Such as the NP/P problems and such. We can give certain logical statements that are true/false for example. Such as "at least one universe exists". :P

[Mark 85]

Re: Really ?

I remember an SF story along these lines (Asimov? Heinlein? Or someone else, not sure) where the entire universe was a young persons simulation in a glass globe for a school science project. Sometimes I wonder at "what is the reality here?" but not often as it boggles my mind.

[d3rrial]

So basically...

... the simulator needs to be in a universe which has either solved entropy or follows different laws of physics?

[Lysenko]

Re: So basically...

If the Universe is simulated the the laws of physics could be as well so entropy might be an artificial "problem". Once you allow the possibility of a simulation then the Heisenberg Uncertainty Principle might just be an externally injected random number generator and entropy might be a deliberate inversion of a natural tendency towards greater organization.

[Anonymous Coward]

Re: So basically...

Or the simulator works the same way computer games do - if a tree falls in the woods and nobody is around, is the destruction rendered?

[Anonymous Coward]

Re: So basically...

Yes it makes a noise. "A tree falling in the woods" and "rendering (it falling in the woods)" are the same things. Simply "falling" and "sound" are the same thing, objects moving.

What you mean is, if the game is not rendering the forest, will the tree even fall? That is only knowable if you know the code. Is the tree falling a pre-determined event (in code or causality) or a random event?

If it is random (true at the event unknowable noise), then you never knew it was going to fall, as the forest was not rendered/calculated/simulated. It never falls and you see a tree standing up.

If you are using a pseudo random number generator (or a known algorithm for the random effects) and know the seed, then you can always recreate the event after the fact, without it needing to "fall".

If it is pre-determined and you do not render it, how do you then know where to put the tree after the fact? Our universe see no distinction between "observed" and "not-observed" for ensembles such as trees (though this changes for individual quanta ;) ).

We could retry the question as "if we see a tree lying on the floor, did it fall, or did it appear spontaneously there?" That is a better question to ask.

[DainB]

Re: So basically...

Sound is an interpretation of observer, not a property of a falling object.

[Anonymous Coward]

Re: So basically...

Why play back the MP3 * (or whatever) of the free falling when there's nobody to hear it?

* randomly selected from a group of MP3's so you don't hear the same sound every time, like that single creaking door sound they use on American TV.

[Anonymous Coward]

Does the fact that we can't simulate the universe not prove that we live in a simulation because if we could then it would be simulations all the way down?

[Anonymous Coward]

It may...

Prove Turing correct...

[Anonymous Coward]

If we are in a simulation then it is generally taken to imply something must be running the simulation. That leads to recursion - as at each higher level something must be running that particular show.

Our existence on the other hand is a simulation. Ourselves, our senses, and the universe are an interaction of some elementary physics that produces the effect of us existing as entities at a particular macro level of perception.

[DropBear]

"If we are in a simulation then it is generally taken to imply something must be running the simulation. That leads to recursion - as at each higher level something must be running that particular show."

I don't see how that follows at all. That would be true only if we were to posit that existence is only possible in a simulation - where indeed someone must be running a higher level one then for each level - but I don't see why we'd need to go that way. Why would it not be possible for an un-simulated form of existence to simulate another?!?

[Anonymous Coward]

"Why would it not be possible for an un-simulated form of existence to simulate another?!?"

At which level the question is still "who/what created that creator?".

The religious would say that their ineffable god "has always existed".

The Universe could be said to have "always existed" in some ineffable form of time and space - and the need for a recursive god/creator becomes unnecessary by Occam's Razor.

[Anonymous Coward]

What if it isn't a simulation but reality?

Einstein once said that "The micro cosmos is the macro cosmos". What if that were true? It would basically refer to the fact that we're not inside a simulation but that our universe is part of something much bigger, something not easily comprehensible.

We already know that although the knowledge about atoms and electrons is mostly correct there's much to them than simply a nucleus and electrons spinning around them, thanks to the expanding knowledge on quantum mechanics. We also know that some things cannot be destroyed, energy can't just "disappear" for example. If you burn a piece of paper then all the basic elements which made up the material are still there, but in a completely different form. Effectively maintaining those basis aspects which made up for the piece of paper or which were 'inside' them.

If we are part of something bigger, why can't it be something which is pretty common in the grand scale of things? So basically theorizing that we, in comparison, are so small that our universe can't "just" be destroyed by any external events.

[Kane]

Re: What if it isn't a simulation but reality?

"It would basically refer to the fact that we're not inside a simulation but that our universe is part of something much bigger, something not easily comprehensible."

Obligatory Discworld quote:

OH, I'VE SEEN THE INFINITE, IT'S...NOTHING SPECIAL.

"Don't be daft, you can't see the infinite, it's...infinite!"

I HAVE.

"Alright then, what did it look like?"

IT's BLUE.

"It's black".

IT's BLUE

"It's black".

FROM THE OUTSIDE, IT'S BLUE, BELIEVE ME.

- Soul Music (Animated)

.

.

.

.

.

.

We gonna get our Pterry icon, or what El Reg?

[tekHedd]

Iconage

"We gonna get our Pterry icon, or what El Reg?"

We have a beer icon. That works nicely.

Death /holding/ a beer, well, that would cover it 100% of course. And be appropriate for El Reg as well.

[Doctor Syntax]

Re: What if it isn't a simulation but reality?

"It would basically refer to the fact that ... our universe is part of something much bigger, something not easily comprehensible."

I don't know about you but I find the universe itself not easily comprehensible let alone anything bigger.

[Francis Boyle]

Citation needed

Ninety per cent of all quotations on the internet attributed to Einstein were in fact Churchill misquoting Mark Twain.

[Filippo]

You don't run a simulation of every single electron. You run a gross approximation that's computationally cheap and good enough for the simulated humans' senses, and you only run the very fine simulations when you detect that some of the sims are performing quantum physics experiments.

[Matthew Taylor]

By that metric, one could argue that Cern scientists are actually endangering the universe. If their particle probings cause the simulator of our universe to have to work extra hard, whoever is running the simulation might decide our universe is over budget, processing-wise, and shut it down.

[Anonymous Coward]

If the framerate drops, nobody inside the simulation would notice - only outside observers.

I did hear an amusing theory that people sleep for 1/3rd of the day because the simulator can't keep up with everybody being awake at once.

[Matthew Taylor]

Or perhaps it can, but with a much coarser simulation fidelity (lack of sleep causes groggy, muddle-brained behaviour) In a similar vein, the greater the world population gets, the less simulation time is available per person, so the stupider we get. :-)

[Anonymous Coward]

Actually I've thought about this more - pervasive CCTV is arguably more dangerous to the simulation, assuming it only does full on calculations for things that are directly observed, with lazy physics for everything else.

Eg: You don't model each subatomic particle in a tennis ball to calculate how it bounces off a wall. It's a predictable behaviour that we already model in computer games in the abstract.

[tekHedd]

"If their particle probings cause the simulator of our universe to have to work extra hard, whoever is running the simulation might decide our universe is over budget, processing-wise, and shut it down."

Who is to say this has not already happened, perhaps more than once?

[Doctor Syntax]

s/some of the sims/the sim

What makes you think there's more than you?

[D@v3]

more than me?

I came to the conclusion that i was the centre of the universe a long time ago, right around the time i got stuck in a machine that appeared to be powered by a fairy cake.

[Omgwtfbbqtime]

@D@v3

Sorry, you are nothing but the construct of a deranged imagination.

Pint for 3 pints at lunchtime.

[Anonymous Coward]

when you detect that some of the sims are performing quantum physics experiments.

Mmmm. And what are the Overlords going to do (e.g.) when there is a planet full of billions of beings using exotic communications devices that all rely on some of the the finer details of quantum mechanics and general relativity?

[Wapiya]

>You don't run a simulation of every single electron. You run a gross approximation that's computationally >cheap and good enough for the simulated humans' senses, and you only run the very fine simulations >when you detect that some of the sims are performing quantum physics experiments.

Hmm, that could be the reason of the particle/wave duality paradox. Normally only the cheap wave computation is needed, but sometime you go full particle processing. May impact the framerate of the simulation or the timebase, but the simulated would not notice.

[Paul Kinsler]

Normally only the cheap wave computation is needed, ...

Wave models are more computationally expensive than particle/ray tracing.

[Anonymous Coward]

The whole point of simulating a universe

Is that you don't simulate the whole thing and waste resources calculating stuff you don't care about. You devote most of your resources calculating stuff that's interacting with things you consider important. Hopefully us, but maybe spiders. Meaning you'd see stuff acting differently whether it was being observed or not and other weirdness. Trees that fell in the forest when no one was around to hear them would NOT make a sound.

Arguing over scale is silly, because not only do you not simulate the whole thing, you don't simulate one as big as the one you live in. Why would you need to or want to? Even if after all that we calculated we couldn't build classical or quantum computers that could hit the required scale that doesn't mean shit. Because that assumes there aren't other ways to build computers we don't yet know about. It wasn't all that long ago that no one had conceived of a quantum computer, so anything that a classical computer couldn't do was "impossible". Even though we can't yet build real quantum computers at any sort of scale, we can at least conceive of the day we when will, and those problems will then be solvable. We have plenty of time to think about other ways to perform computation before anyone actually seriously tries to simulate a universe.

The whole idea we are living in a simulation is total speculation, something that would be almost impossible to prove unless we find a security hole or an easter egg left behind by the developer. So trying to prove that we aren't living in a simulation is equally impossible - more impossible, really, when you consider how difficult it is to prove a negative in general. We can't know what sort of universe our simulation overlords would live in. We have to assume it is pretty similar to our own, otherwise why bother, but it would almost certainly be much larger, probably have a much higher speed of light, and may not even be quantized (i.e. Planck length, Planck time, etc. could be compromises of the simulator and unrelated to the reality of their universe....unless they are living in a simulation as well, of course! :))

[Peter Ford]

Re: The whole point of simulating a universe

While your initial point is fair, the suggestion from this work is that it is not physically possible to make a simulation that covers a tiny bit of what we know - they looked at *one* small quantum effect and found that simulating it to any useful degree was not going to be possible. Now add on all of the other quantum effects and you find that to be sure of the exact nature of just the few particles one sim scientist might be looking at would require an unfeasibly large simulation.

Sure, that's impossible in the universe we know, and since were talking about simulating that universe there's an assumption that there is something of much grander scale outside of our known universe doing the simulation, but we're not talking just orders of magnitude greater, more like orders of magnitude times orders of magnitude...

I think the underlying point is that there's not much chance of us even doing a little simulation that could demonstrate that a simulation is possible (the proof-of-concept is not even feasible) so why worry :)

[DainB]

Re: The whole point of simulating a universe

There's observer effect and faster than speed of light communication between entangled particles, how much more obvious easter egg you need ?

[Doctor Syntax]

Re: The whole point of simulating a universe

"There's observer effect and faster than speed of light communication between entangled particles, how much more obvious easter egg you need ?"

Not Easter eggs. The whole of quantum physics and relativity are just bugs that haven't been sorted out yet. Newtonian mechanics was all that was intended.

[CrazyOldCatMan]

Re: The whole point of simulating a universe

Newtonian mechanics was all that was intended.

That'll be fixed in Universe 2.0. Or in 2.0.1 if the bugfix doesn't work quite right.

[Anonymous Coward]

Re: The whole point of simulating a universe

I hear Venus is being simulated by the beta version. Lets hope they fix those bugs before release.

[Steve 114]

Re: The whole point of simulating a universe

Not that I believe any such thing, but if I lived in a seminary I might posit that the simulation is in the infinitely capable mind of (a) God, and maybe the 'Easter Egg' that proves it is in fact 'Easter'

[Brewster's Angle Grinder]

Re: The whole point of simulating a universe

Been done. To death. And back again.

Definitely Hegel. Arguable Spinoza. Possibly Berkeley. Probably others, depending on how you want to split hairs. Most forms of idealism were grounded in "God". (Some of the related "Omega Point" ideas were spawned by a Jesuit.)

The simulation argument is a form secular idealism for realists: you can claim to be a realist who believes in an external, material world; it's just that the world that surrounds you is only an "idea" (data) in the "mind" (processors) of the real world.

[Anonymous Coward]

Re: The whole point of simulating a universe

The developers of the simulation have been trying their damnedest to get the bugs out of the system by encouraging them to kill themselves off, so as not to upset the spiders. Those pesky humans just won't bugger off though..

[D@v3]

Re: Easter Eggs?

What, like signatures on glaciers?

[McHack]

But when no one's watching...

You don't need such complexity to simulate on the scales no one is observing. A coin is flipped. It's not needed to compute the twenty quadrillion underlying interactions if all that will be observed and recorded is if it's heads or tails.

The simulation outputs are for the observers, and they can be comfortably oblivious of 99%+ of anything not observed. What game designer simulates every drop of the unseen fountain two towns over?

[AndrueC]

Re: But when no one's watching...

The simulation outputs are for the observers, and they can be comfortably oblivious of 99%+ of anything not observed

Quite. All good programmers realise that the users only know what they tell them.

[Doctor Syntax]

Re: But when no one's watching...

"the observers"

In the plural? Do you have a proof there's more than one?

[nijam]

Re: But when no one's watching...

> The simulation outputs are for the observers...

... but we are not those observers; there's no point in us speculating what the simulation is or isn't simulating.

[Anonymous Coward]

Re: But when no one's watching...

We may not be the observers, but we'd obviously be something important to the observers. Why bother to simulate consciousness in everyone if that's the case? Though its possible I'm the only one with a simulated consciousness, and you all are getting crude approximations - especially amanfromMars 1!

If you think about it though, maybe we ARE the observers. The difficulty in understanding where consciousness springs from would be understandable if its source was outside the simulation. The lifetime of a normal human might be an afternoon for our real selves, and our universe is basically some juiced-up combination of Facebook, the Sims and World of Warcraft. That's why there are so many minor celebrities these days, people got bored of playing slaves, serfs and other downtrodden folk after a while.

[Francis Boyle]

Re: But when no one's watching...

Why assume anyone is simulating consciousness? Maybe whoever is running the simulation is simulating a universe, that is they are simulating the fundamental laws of physics (whatever they are) and consciousness is just something that happens. On my reading, it's this sort of simulation (perhaps emulation would be a better term because the idea is that the simulation is function identical to the real thing) that the paper is arguing against, not the Matrix type which is really just a video game on steroids and can use all the workarounds people have been talking about.

[Anonymous Coward]

“we live in a simulation" trope

perhaps, with your infinitely superior computing power, you already found out it's impossible. Unfortunately in my universe we ain't there yet.

[Anonymous Coward]

Surely all the paper is saying is that you can't adequately simulate quantum phenomena using "classical computational resources", i.e. non-quantum computers. So what if you had quantum computers to run the simulation?

[Anonymous Coward]

Then it's not a simulation.

By all means... how do you propose carving a "perfect human stone statue that is alive"?

Or how do we "make a computer so powerful it tastes like Strawberry"?

Or "Fly so fast we reach Dubstep"?

If we "perfectly simulate" something, we are no longer using an inappropriate material. Stone cannot process like biology can, we can never "carve a perfect human from stone". It's an impossibility. So certain computation cannot be done with Turing machines. We can however "clone" a human, at which case, we have a real human, not a pretend one. ;)

Certain logical principles are not other logical principles. If we have a spare universe, the same size as ours, using quantum particles in the same position, calculating the same interactions, of the same events... we no longer have a simulation, we have a universe... and not even a "model/toy" one at that. :D

[Brewster's Angle Grinder]

Re: Then it's not a simulation.

TL;DR There is only one true map: the thing itself.

[Roj Blake]

Re: There is only one true map: the thing itself.

Melchett: Course I am. Now let's talk about something more jolly shall we? Look, this is the amount of land we've recaptured since yesterday.

[Melchett and George move over to the map table.]

George: Oh, excellent.

Melchett: Erm, what is the actual scale of this map, Darling?

Darling: Erm, one-to-one, Sir.

Melchett: Come again?

Darling: Er, the map is actually life-size, Sir. It's superbly detailed. Look, look, there's a little worm.

Melchett: Oh, yes. So the actual amount of land retaken is?

[Darling whips out a tape measure and measures the table.]

Darling: Excuse me, Sir. Seventeen square feet, Sir.

[Anonymous Coward]

Douglas Adams nailed it:

"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space."

[D@v3]

Douglas Adams nailed it

[End Of Message]

[Mage]

Simluator

Why do some people want to believe we are in a simulator?

Is it part of their Transhumanism "Religion"?

Coat has Occam's razor in pocket.

[alain williams]

Re: Simluator

Coat has Occam's razor in pocket.

Don't cut your fingers on it when you reach for your bus pass.

[Anonymous Coward]

Re: Simluator

>Don't cut your fingers on it when you reach for your bus pass.

Ah but you're making an assumption they travel by bus.

[find users who cut cat tail]

Re: Simluator

It seems the Universe can be on the fundamental level described using mathematics, with a relatively few simple laws (for some values of ‘few’ and ‘simple’ anyway). If it is a simulation, that is exactly the thing to expect. If it is not, well, it can still work this way, but it is rather surprising that it does. Why should it?

[Anonymous Coward]

Re: Simluator

Why would algorithms suggest "simulation"? It could suggest preferred starting states. It could suggest a method/system of control/organisation. But would it suggest fundamental "simulation"?

Besides such questions are somewhat pointless until we know certain things such as the shape of the universe (flat space-time or curved or doughnut etc ). Then we can consider if/how it is projected into our dimensions and it's possibility for fundamentals.

[Aitor 1]

Re: Simluator

It would work like that because math was invented to describe the universe that we form part of in the best way possible.

So of course the universe is going to be able to be described by maths, otherwise we would have to invent maths 2.0.

While I disagree with the "you cannot simulate it", I think that a good enough simulation would be as good as a non simulated one, so why bother? Anyway we will figure it out eventually, and I think this is not a very interesting question to make.

[DainB]

Re: Simluator

Because having multiverse and string theories on one hand and simulation on another simulation actually explains most of quantum weirdness and easy to understand.

[Anonymous Coward]

Re: Simluator

The simulation argument applies Occam's razor. It proposes that one of 3 things must be true, and the other two seem at least as implausible as the simulation hypothesis.

[The Indomitable Gall]

Re: Simluator

" The simulation argument applies Occam's razor. It proposes that one of 3 things must be true, and the other two seem at least as implausible as the simulation hypothesis. "

Nope -- it's just a shoulder shrug. Just like the deity solution, it postulates the unprovable.

Testable theories can be considered secular in the traditional sense in that they only concern themselves with the mechanics of the physical realm -- most of our science originates in the secular philosophy of religious scientists.

While the simulation hypothesis is not "religious" per se, it is certainly not secular, and it's just as impossible to prove or disprove as any deity.

[Milton]

Unconvinced

I do not say we are living in a simulation, but I'm not 100% convinced by the narrowness of the explanation given. As others here have said, if a simulation includes (a) programmatically influencing the "thought" processes of those being simulated, (b) is capable of summarising what is *purportedly* ineffably complex, and (c) uses a degree of randomisation which we are *encouraged* to view as quantum weirdness, then I don't see that our apparent perceptions of the universe can be trusted as proof that it ain't a simulation.

Indeed, you might even argue that presenting the appearance of quantum ineffability (weirdness, if you like: or anything that hinges from Einstein's observations about "spookiness") is a very neat way of making it impossible for the Simulated to prove that that is what they are. If the rules presented as fundamental by the simulation had stopped at Newtonian, classical mechanics, then sometime between 1700 and 1905 we'd have penetrated the fiction and the game would be up.

In short, you can't disprove a simulation theory by assuming that the perceptions those doing the disproving are NOT being interfered with. Indeed, it would seem a logical contingency to apply.

[Anonymous Coward]

Re: Unconvinced

Bells theorem and such like can show that Quantum particles are not Turing simulated. So we would have to consider a Quantum computer.

If we consider a Quantum computer (as we have to since all observations suggest actual Quantum effects, not simulations of such), then it has to be the same size as the observable universe, to the same detail at the plank scale.

To skip any of this, would allow an error to be detected in the Quantum results (CERN etc) and we could show that Quantum Mechanics falls apart at certain scales (say stars so far away the light is not simulated, and the probabilities fall apart).

So while a real simulation would want to limit computational strain, if limited by resources, our current universe has a 13 billion or so lightcone and a BIG indication it's somewhat fundamental in our space/dimension.

However, given near infinite anything, anything is also possible. You would just have to propose an infinitely big simulation running our universe on it. Why though propose that, what observation do you have to disprove ~26 billion lightyears and ~13 billion years worth of particle interactions (or "observations" depending on the language used)?

[Alan J. Wylie]

Hidden Variables?

Hidden variable theory

[Anonymous Coward]

Re: Hidden Variables?

Thank you! I wish I could upvote more. While the sea of people complaining about the article is understandable... peoples lack of ability to consider things and learn is sad to see.

So I do hold out hope when other people, like you, can see the actual principles involved and the limits or possibilities allowed or disallowed by them.

[Duffy Moon]

One way to find out for sure

Build a Total Perspective Vortex. If it doesn't affect you, you're in a simulation.

[Dan 55]

I don't know if we're in a simulation

But lately it seems like someone's overclocking it.

[Zmodem]

just say its some quantum paradox because quantum computers can do quantum things

[Matthew Taylor]

Sonic the Hedgehog

In other news, Sonic the Hedgehog failed to make a viable computing device out of gold rings and other items lying about in his world, and declared that he had proved mechanical computation was impossible.

[Shaha Alam]

if we're going to assume a computational simulator...

why not assume it's a very big computational simulator? it might even be a hypervisor simulator with more than one simulation running at the same time.

seems like the problem here is lack of imagination.

[Anonymous Coward]

Re: if we're going to assume a computational simulator...

We can imagine the impossible. Lack of imagination is not a problem.

[Nuno trancoso]

Total bollocks

One can argue that the only thing capable of holding our universe's full state information is by definition the universe itself. No problem with that. Thus, WE can't build that simulator. But the whole shebang falls apart when you actually try to infer that what we know as "the universe" would be the "actual universe" if we were a simulation. The "reasonable" inference is that we always simulated things SMALLER than our universe, thus, if we were a simulation, the "real universe" would be quite big enough to hold "our universe"'s state information with plenty of room to spare. The Earth is quite big from an ant's perspective, but quite small from even our galaxy's perspective. Always a matter of scale.

[Tessier-Ashpool]

Don't worry about the scale of it

It's just numbers at the end of the day. God can have any number he likes.

Adherents of the Many Worlds Interpretation of Quantum Mechanics tell us that anything that can happen does happen, in a vast multiverse. If correct, the universe is doing a lot more number crunching than meets the eye. It also neatly kicks true randomness into the long grass: if everything happens there's nothing to make a choice about which apparently random event will take place compared to another. All possible events happen, so no random choices are truly made.

I haven't a clue why our universe really does what it does, so I'm in no position to say how it could be a simulation, other than in glib human terms. But I do find the idea compelling that there's computation going on at the deepest level. It would be a rational explanation for General Relativity, for example. Einstein's field equations tell us that time slows down in the vicinity of a Black Hole, but the why of it all rapidly fizzles out once the equations containing mass and spacetime start referring to each other. If something is doing a lot of computation, however, the vast number of interactions in the vicinity of a Black Hole could seriously slow down your 'virtual machine', or whatever you like to call it. Voila, time dilation.

[Ralph the Wonder Llama]

El Reg can't help feeling that the explanation is missing something

Yeah, me too, but I'm fucked if I know what it is.

[Nick Z]

The human brain itself is a simulator of the universe

Our experience of the universe is created by our own brain.

There is no such thing as color or solidity or even movement of time out there in the universe. All of these experiences are created by our own brains.

Which literally means that we all live in a simulated universe.

The universe itself isn't simulated. But our perception and experience of it is simulated.

[The Indomitable Gall]

Re: The human brain itself is a simulator of the universe

Don't you mean "there is no spoon"...?

[Anonymous Coward]

So we can't be living in a simulation

...which is exactly what the simulator would want us to think.

[Anonymous Coward]

I'm afraid to tell you that this is all a dream I'm having during a particularly dull meeting after a very heavy and beery lunch. Now, if you'd all keep quiet, I'm just coming up with the latest excuse why the Vega+ console will be delayed another nine months.

In case you want to know, the real universe is just like my dream, except in the real universe Girls Aloud never split up.

[a pressbutton]

Who cares - the real question is

real real or simulated real

.. can we break it?

[The Indomitable Gall]

Re: Who cares - the real question is

Oh god.... you've just given me a terrible thought...

...what if the device we're being simulated on is used in a higher-dimensional episode of "Will It Blend"...?

[hammarbtyp]

on the other hand...

or maybe that's what we've been programmed to think....

I'll get my tinfoil hat

[Jonathan 27]

If we're in a simulation, then how do we know if it's possible to simulate our universe. Maybe physics is totally different outside the simulation. The simulation could be powered by a Dyson sphere, or a thousand Dyson spheres, there is literally no limit to the possibilities. This whole line of thinking is rather silly, the idea that we're in a simulation is a non-falsifiable statement. No amount of rational thinking can disprove it, although I suppose there might be some sort of currently unknown way to prove it, possibly.

Do i believe we're in a simulation? No, probably not. But that doesn't mean that this line of thinking proves anything. All this paper proves is lack of imagination. Also, the paper doesn't put forward the conclusion that the author of this piece infers. In fact that inference dies immediately if take away the idea that the simulation in question could easily be running on a quantum computer or another more sophisticated computer that we can't even imagine.

[Anonymous Coward]

Argument from Scale

Seriously:

It seems unimaginative and a little anthropocentric to suggest that because the simulator needed would have to be incredibly large, it is thus impossible.

Not-so-seriously:

Overlord 1: "They are doing another quantum experiment..."

Overlord 2: "Enable the high-resolution uncertainty but first, take a back-up."

[Morten Bjoernsvik]

catsimulator

IBM built a massive blue gene for simulating a cat brain:

http://www.artificialbrains.com/darpa-synapse-program#catsimulation

And there was massive critism because the neuron simulators were way too simple, so it was a very very stupid cat, even though the size was good.

[Valerion]

First rule of simulation

Never, EVER, let the things you are simulating believe it's possible to run such a simulation.

[Anonymous Coward]

If I were an omnipotent alien god in need of funding to budget their universe simulation project that has been running for a few eons already without tangible results, if I had that looming deadline to provide a detailed cost-benefit analysis to my omnipotent alien god supervisor - I would also introduce puppet scientists entities in my simulation to make sure those other cute simulated entities don't start having funny ideas and spoil the results.

[nijam]

> ...an omnipotent alien god in need of funding ...

If you need funding, you're not omnipotent.

[CrazyOldCatMan]

If you need funding, you're not omnipotent.

Indeed. And also, if you have a supervisor then, by definition, you ain't omnipotent..

[Matthew Taylor]

Omnipotent in our universe, not in its own.

[anthonyhegedus]

If we live in an exact simulation of a real universe, then there's no observable difference between the simulation we live in and the real universe, so it isn't a simulation, it's just another universe.

[Anonymous Coward]

The difference is very much observable if you're the tech in charge of replacing the simulation's UPS without tripping the power by mistake: you could be fired.

[Blank Reg]

A new religion

This whole simulated universe idea is just stupid.

Just because we don't understand how quantum physics works is no reason to make up crap like a simulated universe. That's how religions get started, and we've got more than enough of those already.

[tecnoworld]

Bullshit

1) everything that exists can be simulated (given enough resources: computational power, memory, energy, time)

2) we can't assume that the physics of the "world" in which the "simulation" runs is the same as ours

3) Musk is right: we are in a simulation and he is just an avatar for a "person" from the "outer world". That's why he could become as rich as he is, exploiting the rules of the system

[Tim Soldiers]

Doesn't PI preclude a digital universe ?

[theN8]

Roundworld

Roundworld is a sphere-shaped world. Yes, it is silly, but people seem to be able to stand on it, so we shouldn't worry too much about it. It lies in a universe created by the wizards of Unseen University, as a way to use up the excessive magical energy generated by the splitting of the thaum. (However it should be noted that travel to the Roundworld and references was possible before the wizard's creation so it may not have happened yet.) Hex watches over the Roundworld, and can move small things in it and influence it slightly. Apart from that, it is (in theory) completely isolated from other universes, and there's no magic in it, not even essential elements like narrativium. There aren't even any gods. After several failed attempts, the wizards managed to create a nice planet (although it's not plane at all, which is quite depressing) where life started to develop.

For all intents and purposes, Roundworld is "our" planet Earth - it is home to a human civilisation which mirrors our own, though several other civilisations have risen and fallen in Roundworld's past, including the crabs and dinosaurs. Roundworld's human inhabitants have not led an untroubled existence; their history was severely threatened by an infestation of Elves, who twisted the stories of Roundworld humans (notably William Shakespeare) to their own ends, and later by the Auditors of Reality, who objected to the consequences of Charles Darwin's Origin of Species. The Wizards acted in both cases to protect their preferred Roundworld history; they feel a certain level of responsibility for the entire universe they have created, and especially for the humans who dwell in it.

[D@v3]

Proof! (well, it's written in a book, so it must be proof)

"I speak of none other than the computer that is to come after me," intoned Deep Thought, his voice regaining its accustomed declamatory tones. "A computer whose merest operational parameters I am not worthy to calculate - and yet I will design it for you. A computer which can calculate the Question to the Ultimate Answer, a computer of such infinite and subtle complexity that organic life itself shall form part of its operational matrix. And you yourselves shall take on new forms and go down into the computer to navigate its ten-million-year program! Yes! I shall design this computer for you. And I shall name it also unto you. And it shall be called ... The Earth."

[handleoclast]

Fatally flawed assumption

They're assuming that the universe doing the simulating is exactly like the one being simulated.

Maybe the universe running the simulations doesn't have weird quantum effects. Maybe they only exist in our simulated universe, thrown in to make us thing we're not being simulated.

[Will Godfrey]

Can't be done?

Insufferable arrogance.

[GrapeBunch]

Chess

To play a perfect game of chess also requires a computer larger than the known universe, or more time than already shows on its clock. But hardware to play a typical single-session tournament game against a cyber-unaided fleshly world champion, and win most of the time, is well within the ambit of most first-world households. Even laxer, to beat the head of household of 99.99% of the households could be job done with just a portion of the computing power of an old mobile phone. So you don't need much to make a "good enough" simulation of perfect play at chess. A buzzword could be asymptotic.

The simulation in the story is simpler, as the stumbling block is to simulate quantum, apparently random effects. All they need is a better random simulator than you have. What they need to fool you is next month's random simulator. It's like, some decades ago, when driving to the next chess tournament in a car with other like-minded individuals, one of us in the back seat came up with (paraphrasing): "God is no more than what determines the result when Heisenberg's Uncertainty Principle seems to be in play." Or in the present context: "God is a slightly better random number generator."

[Anonymous Coward]

Re: Chess

Sorry. You dail to understand the principles on multiple levels.

Think for a moment. If one particle for one instance is not simulated, what happens after? Does it reappear into existence? Do we randomly give it a position? Do we trace vack it's history to work it out? What are the fundermental problems each option causes?

[tekHedd]

That doesn't seem physically possible!

This is what happens when you tell a bunch of engineers that something is not possible.

[Snowy]

Maybe instead of simulating the universe they just created one to observe :)

[RichardB]

I can't help thinking that there's another conclusion here

What they are really concluding is that in order for this universe to be a simulation, it requires a whole new form of computing capability that we are not currently aware of.

In other words the simulation can only be from us in the future, or a terrifyingly more technologically advanced species than ours.

Except of course that if we are a simulation, then us in the future can't create us in the past, unless of course they have taken over the simulation and are themselves running a historic 1st person simulation game, or indeed broken out of the simulation and somehow sequestered a server for their own creative purposes. In which case they wouldn't necessarily be us, but an earlier generation of sim...

Not to mention that if we are a simulation we are not strictly going to be in the same classification system, let alone similarity of species to the programmers and engineers that created us.

What fun.

[Anonymous Coward]

My thing is, is how can you justify saying building a machine powerful to simulate a universe as big as our own is impossible. Firstly, if we are living in a simulation, then whomever created it most certainly has advanced farther than us technologically. For a loose comparison let's use the power of the first computer compared to the power of, let's say, the new IPhone X with our current technology being the first computer and the simulators creators technology being the iPhone X. I'm not saying this is true but I'm not doubting the technology doesn't exist simply because we don't have it. Secondly, I read an article very recently talking about the power it would take to run such a simulation and of course it said it would take a lot. However, it also said the power required could be lessened to the simulation only simulating what is needed when it's needed. For example, let's say you're sitting in your room with no view of your hallway. It's quite possible that your hallway isn't actually there until you open the door.

[JimmyPage]

The worrying thing is ... a simulated universe

would pretty much be a paradigm of Occams razor when it comes to explaining the universe. Even (or *especially* "woo").

I'm sure the vast majority of commentards could imagine scenarios in which "woo" is actually a snafu in the program or the computer and OS it's running on.

Ghosts for example. Just some unzeroed memory that has retained data from a previous run ?

Time travel ? Well obviously - just restart the program with different parameters. And so on.

No quantum theory of gravity ? Well, Universe 1.0 was launched a bit early. They forgot to design that bit.

Taking the analogy further, supposing there *are* bugs in the simulation. If there are (and experience suggests there must be) then suppose further that these bugs can be exploited by mumbling in some weird language whilst prancing naked around a yew tree in a stone circle ?

All of this aside, I would be curious to know if there is a movement in science which is specifically looking for bugs in a simulated universe. Or, at the very least, trying to come up with a definite test ?

(See also: If a tree falls in a forest ....)

[Tigra 07]

Level 4...

If this universe is indeed a simulation does anybody know how to beat the boss i'm stuck on?

It's called a Trump and has massive firepower

[ken jay]

I have been playing role playing games since a little known game called alternate reality the dungeon came on on commodore 64 disk, that one game alone compared to something like destiny 2 or one of the newer MMO`s shows the leaps we have made in virtual worlds, if we look at moore`s law over just a mere 30 years what will the future give us, maybe us running sentient beings on a virtual world while actually being in one ourselves.

[PNGuinn]

Can we look at this another way?

Could this potentially be a quantum leap in frog computing?

[Brian Allan 1]

A total lack of imagination of what technology could accomplish in a thousand, million or billion years! Look at what has been accomplished in the past hundred years...

[Anonymous Coward]

Theories

What if... EMdrive is actually exploting a bug in this simulated Universe?

If you think about it, the more precisely parameters are measured the smaller the effect gets.

Just as Heisenberg suggests, measuring one parameter precisely causes other parameters to change.

Corollary to this, perhaps the JimmyPage argument is correct and what is being measured is potential energy crossing the dimensional barrier from scientists doing experiments in *other parallel Universes* wondering why their EMdrives are not working properly yet early models seemed to.

[adam 40]

The Size of the Observable Universe, and the Planck length

These two artificial bounds would appear to be compelling evidence that "our" Universe is limited in size and complexity (granularity), to enable it to be easily modelled from outside.

If you are going to design a simulation, you first define the resolution (in this case the Planck length and time) and overall volume of the space (limit of the observable universe). The unusual thing, I suppose, is that we can observe both of these limits, despite being inside the simulation.

My son already works with Avagadro-number-sized simulations, they seem to be standard in Theoretical Physics, it seems a small step to scale up by a few hundred orders of magnitude.

If we didn't have quantum effects at the bottom, and the whole thing were continuous, and unbounded, THAT would be a difficult thing to simulate.